Question: $ { {-3} \times \left[\begin{array}{rr}{2} & {-2} \\ {3} & {1} \\ {2} & {-1}\end{array}\right] = {?} } $
Answer: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rr}{-3}\times{2} & {-3}\times{-2} \\ {-3}\times{3} & {-3}\times{1} \\ {-3}\times{2} & {-3}\times{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-6} & {6} \\ {-9} & {-3} \\ {-6} & {3}\end{array}\right]}$